DE60200094T2 - System and method for regulating a braking force of a vehicle - Google Patents

Description

BACKGROUND OF THE INVENTION 1 , Field of the Invention

The invention relates to a Driving state control system for a motor vehicle that regulates the driving state of a vehicle when it moves backwards or backwards on a rising road, especially when the driver's foot is away from the brake pedal moved to the accelerator pedal.

2. State of the technology

A method for automatic is known Applying a braking force to a wheel of a motor vehicle when the vehicle moves from the brake pedal when the driver's foot moves Moved backwards to the accelerator on a rising road. For example, disclosed JP-A-10-16745 a driving state control system according to the preamble of claim 1, wherein a braking force is applied to the wheels if it is determined that the vehicle is opposed to that of the driver selected forward drive moved backwards, causing the backward movement speed of the vehicle is reduced. According to the disclosed procedure the amount of on the wheels acting braking force regulated in such a way that the backward movement speed of the vehicle exceeds a predetermined upper limit. The backward movement speed of the The vehicle is therefore kept within a constant range. According to the procedure disclosed hangs the size of the on the wheels acting braking force only from the speed at which the vehicle is moving backwards but not from an increase in the rate of backward movement of the vehicle d. H. the acceleration of the vehicle. In the above Case leaves the backward movement speed of the vehicle is therefore insufficient decrease when the backward movement speed of the vehicle is increasing at a high rate.

Further can be continuous Execution of the Brake force control when the vehicle is moving backwards, the driver lead to the assumption that the regulated backward movement speed The natural Backward movement speed of the vehicle. The regulation to reduce the speed of backward movement of the vehicle was original meant for, for example in the event of a change the foot position the driver to intervene away from the brake pedal towards the accelerator pedal to keep the driver in its intended activity temporarily to support. For this reason, the regulation requires the driver to do this as part of the actuation support Have the brake and accelerator pedal operated appropriately.

A brake actuator is known which in a traction control system to limit wheel slip while acceleration or in a cornering behavior control system, that applies a braking force to a specific wheel of the vehicle, is used. The known brake actuator can be temporary Loading the wheels can be used with a braking force to the backward speed of the Decrease vehicle. Will the regulatory system for abatement the backward movement speed of the vehicle however for a longer one Period would be used a stronger one and more durable actuator required.

SUMMARY THE INVENTION

The invention is based on the object Driving state control system for to create a vehicle with which the driver can be made to while of support of actuation the brake pedal when starting on an uphill road and operate the accelerator pedal in an appropriate manner.

To solve this task, the Invention according to claim 1 a driving state control system for Regulation of the on the wheels of the vehicle Brake force before if the actual direction of travel of the vehicle to the Target driving direction of the vehicle according to the operation selected by the driver is opposite. The driving state control system includes a vehicle operating state detection device that determines whether the driver's operation is the forward drive or reverse drive is, an actual direction of travel detection device that the actual direction of travel of the vehicle, a braking device that is independent of the brake application the driver exerts a braking force on a specific wheel, and a control device that applies the braking device controlled in such a way that the braking force is applied to a wheel, which is a direction corresponding to the actual direction of travel of the vehicle rotates when the one determined by the operating state detection device Target travel direction of the vehicle to that of the actual travel direction detection device recorded actual direction of travel of the vehicle is opposite, and the application of braking force the braking device stops after the braking device for a predetermined the first duration was controlled continuously.

The control unit controls the operation of the braking device such that in the case in which the direction of travel desired by the vehicle driver and the actual direction of travel of the vehicle are opposite, ie when the vehicle is moving backwards on an uphill road, the braking force is applied exerting a wheel that rotates in the direction in which the vehicle is moving backward. In this way, the backward speed of the vehicle can be reduced. The control unit ends the regulation after a predetermined period. This measure effectively contributes to causing the driver to operate the brake and accelerator pedals, and at the same time prevents the brake device from operating continuously for a long time, thereby ensuring protection of the brake device.

Advantageous embodiments are the subject dependent Expectations:

In the driving state control system will be the one exercised on the bike Braking force slightly reduced if the braking force is for a period which is longer than a second duration that is shorter is as the first duration, is regulated continuously.

In the driving state control system reduces the control unit the pressure of the braking force in such a way that the braking force exerted on the wheel is not ended immediately, but with a small gradient decreases. This measure prevents a sudden change the backward movement speed of the vehicle and enables it, the driver announce that the scheme to reduce the backward speed of the vehicle is ended. Accordingly, this measure provides the driver enough Time to apply the brake pedal and / or the accelerator pedal.

In the driving state control system regulates the control unit the size of the on exercised the wheel Braking force, the size of the braking force applied dependent on on the size of the acceleration of the vehicle is changed in the actual direction of travel.

In the driving state control system regulates the control unit the distribution of the braking force on an increasing road top or bottom wheels exercised becomes so that the braking force that is exerted on underlying wheels increases with increasing gradient.

In the driving state control system, which has a direction of rotation detection device which determines the direction of rotation each wheel of the vehicle, the control unit exercises independently of the brake application the driver a first braking force on at least one wheel, which is in a turns in the opposite direction to the target direction of travel the direction of rotation detection device is detected, and a second Braking force on at least one wheel that is in one of the desired direction of travel corresponding direction rotates, the first braking force on the at least one wheel that is in the opposite direction to the direction of travel turns depending is determined by the driving state of the vehicle, and the second braking force on the at least one wheel, which is in the desired direction of travel corresponding direction rotates, depending on the state of rotation of the Rads is determined.

SHORT DESCRIPTION THE DRAWINGS

The invention is by reference described in the accompanying drawings, in which for illustration Similar features the same reference numerals are used and in which:

1 4 is a schematic diagram showing a powertrain and a hydraulic pressure control system of a motor vehicle with a driving state control system according to the invention;

2 FIG. 12 is a schematic diagram showing a hydraulic pressure control system of a brake actuator for brake force control for one of the wheels of the vehicle;

3 FIG. 12 is a block diagram showing a general control device of an electric system and a hydraulic system of the driving state control system;

4 14 is a flowchart showing a control routine of a backward movement limit control according to a first embodiment of the invention;

5 Fig. 12 is a graph showing the relationship between the wheel cylinder pressure and the time required to execute the backward movement limit control;

6 FIG. 14 is a flowchart showing a control routine of a backward movement limit control according to a second embodiment of the invention;

7 FIG. 14 is a flowchart showing an example of a hydraulic pressure control subroutine executed in step S200 of FIG 6 flowchart shown is to be executed;

8th 14 is a flowchart showing a control routine of a backward movement limit control according to a third embodiment of the invention;

9 FIG. 14 is a flowchart showing an example of a backward movement limit control subroutine executed in step S312 of FIG 8th flowchart shown is to be executed;

10 FIG. 4 is a flowchart showing an example of a slip limit control subroutine that is executed in step S314 of FIG 8th flowchart shown is to be executed; and

11 FIG. 4 is a diagram for determining a target control pressure P defined by a change in the wheel speed.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to the accompanying drawings are now preferred embodiments of the invention explained.

Embodiment 1

1 schematically shows the drive train of a motor vehicle with four-wheel drive, which includes a driving state control system according to a first embodiment of the invention. The output torque of an internal combustion engine 1 is by means of a converter 2 converted and via a translation device 3 on a front wheel drive shaft 4F and a rear wheel drive shaft 4R distributed. The front wheel drive shaft 4F stands over a front differential 5F in conjunction with a left front axle shaft 6 FL and a right front axle shaft 6 FR connected to a left front wheel (FL) or a right front wheel (FR). The rear wheel drive shaft 4R stands over a rear differential 5R in conjunction with a left rear axle shaft 6 RL and a right rear axle shaft 6RR connected to a left rear wheel (RL) or a right rear wheel (RR). The output torque of the internal combustion engine 1 is therefore transmitted to the wheels FL, FR, RL, RR according to the mechanism explained above. The translation device 3 has selective operating positions, namely an overdrive for a translation into rapid, in which the output torque of the converter 2 without changing the speed on the front and rear wheel drive shafts 4F . 4R is transmitted, and a slow gear for a translation into slow, in which the output torque of the converter 2 at a reduced speed on the front and rear wheel drive shafts 4F . 4R is transmitted. The translation device 3 has an integrated central differential gear to compensate for a speed difference between the front and rear wheel drive shaft 4F . 4R on.

The left and right front wheels FL, FR and the left and right rear wheels RL, RR each have a hydraulically operated braking system 20 on. The braking system 20 includes a wheel cylinder 21 and a master cylinder 30 , both of which are filled with a working fluid and are kept in fluid communication via a hydraulic system. A brake actuator is connected to the hydraulic system 200 to increase and decrease the working fluid pressure regardless of the driver operating the brake pedal.

2 schematically shows the brake actuator 200 , the brake actuator 200 is controllable to control the working fluid pressure in each of the brake systems 20 to regulate the wheels FL, FR, RL, RR independently of one another. The hydraulic systems of the brake actuator 200 that are used to regulate the wheels FL, FR, RL, RR are identical, so that in 2 only one is shown as a representative.

The master cylinder 30 and the wheel cylinders 21 stand over a line 201 that with an electrically actuated interruption valve 210 is provided, which is open without power, in fluid communication. The working fluid pressure is regulated with the help of an electrical current that is connected to this interruption valve 210 is applied to thereby the interruption valve 210 close and a working fluid flow between the master cylinder 30 and the wheel cylinder 21 to interrupt. In a section of the line 201 between the cut-off valve 210 and the wheel cylinder 21 is an electrically operated holding valve 220 provided that is open in the de-energized state. The holding valve 220 is energized, thereby closing it between the stop valve 220 and the wheel cylinder 21 existing hydraulic system is kept in a closed state.

At a section between the holding valve 220 and the wheel cylinder 21 is the line 201 with one line 202 connected via which the working fluid to a surge tank 40 can flow. This line 202 is with a pressure control valve 230 provided (which is closed in a de-energized state). The pressure control valve 230 is selectively switched to its two operating positions by applying a control signal with two states, ie an excitation state and an de-excitation state. Thus, by regulating the duty cycle of the pressure control valve 230 control signal present the line 202 with the line 201 connected or from the management 201 be separated.

One from an electric motor 50 driven pump 51 serves as a hydraulic pressure source during braking force control. The pump 51 is at its pressure connection via a line 203 at a section between the cut valve 210 and the holding valve 220 with the line 201 connected. On the line 203 is on the side of the pressure connection of the pump 51 a check valve 253 provided to prevent over the line 203 Working fluid to the pump 51 flowing back.

On the other hand is the pump 51 over a line 204 at their suction port with the expansion tank 40 connected. On the line 204 are check valves 251 . 252 provided to prevent over the line 204 Working fluid to the expansion tank 40 flowing back.

The administration 204 is over a line 205 working on a section between the check valves 251 . 252 is connected with an expansion tank 31 connected. The pump 51 can thus over the lines 205 . 204 in the expansion tank 31 Aspirate stored working fluid. On the line 205 is an electrically operated suction valve 240 provided (which is closed without power). The suction valve 240 is for opening and closing the line 205 switchable.

The one from the pump 51 and other various types of brake actuator formed 200 can be controlled by a control unit 100 drive.

According to 3 becomes the control unit 100 with the output signals of various driving state sensors of the vehicle, for example from the Wheel speed sensors assigned to wheels FL, FR, RL, RR 110 for detecting the direction of rotation and the speed of the respective wheel, a gear lever position sensor 120 for detecting the currently selected shift position of a shift lever, a brake pedal sensor 130 for detecting the amount of operation of a brake pedal 10 , an accelerator pedal sensor 140 for detecting the operation amount of an accelerator pedal, a gear sensor 150 for detecting the gear of the transmission device selected by the shift lever 3 and a longitudinal acceleration sensor 160 for detecting the longitudinal acceleration of the vehicle. The wheel speed sensor 110 is formed from a sensor that is able to detect not only the wheel speed but also the direction of wheel rotation.

2 shows how the control unit works 100 100 , in particular the way of regulating the brake actuator 200 when the vehicle is reversing on an uphill road. The regulation serves to limit the backward movement of the vehicle. Below is this regulation of the brake actuator 200 therefore referred to as a "backward movement limit control". The flowchart in 4 shows an example of one from the control unit 100 for one of the wheels of the vehicle control routine of the backward movement limitation control to be executed, which is similarly executed for the other wheels of the vehicle.

The routine of in 4 The flowchart shown begins with the switching on of an ignition switch. First, in step S101 the output signals of the sensors ( 110 . 120 . 130 . 140 . 160 ) or the switch ( 150 ) received. Then, step S102 is carried out to determine the target driving direction of the vehicle driver depending on that of the shift lever position sensor 120 to determine the shift lever position. When the shift lever is in a forward drive position, it is determined that the driver wants to drive forward. On the other hand, when the shift lever is in a position to reverse drive the vehicle, it is determined that the driver wants to reverse.

In step S104, the actual direction of travel the vehicle, d. H. forward or backwards, definitely.

For example, if the vehicle is started on an uphill road, the driver must get his foot off the brake pedal 10 move away to the accelerator pedal. This can temporarily lead to a condition in which neither the brake pedal 10 the accelerator pedal is still depressed, with the result that the vehicle moves backwards. Furthermore, the wheels FL, FR, RL, RR of the vehicle turn in the direction in which the vehicle is moving. Accordingly, the actual direction of travel of the vehicle can be determined as a function of the direction (s) of rotation of a specific wheel or all wheels.

Because the driving state control system this embodiment can be used in a motor vehicle with four-wheel drive it is determined in step S102 that the vehicle is currently in a Direction, which is opposite to the target direction of travel if at least one of the wheels rotates in a direction opposite to the target direction of travel.

After determining the actual direction of travel of the Vehicle in step S104, the process goes to step S106 in which is determined whether a flag F is set to 1, which shows that the backward movement limitation scheme is currently running. The flag F is normally open at the start of the control routine 0 set. Accordingly, NO is obtained in step S106, whereupon the process goes to step S108.

In step S108, it is determined whether the driver's target direction of travel with the actual direction of travel of the vehicle matches. If the driver's target direction of travel with the actual direction of travel of the vehicle matches YES is obtained in step S108, and the process then goes back.

If the driver's target direction of travel is Actual direction of travel of the vehicle is opposite, in step S108 NO received, and the process goes to step S110. In step S110 the flag F is set to 1 and the process goes to step S112, in which a timer for measuring the since the start of the backward movement limit control past time is activated.

As described above, when the vehicle moves backward, the wheels FL, FR, RL, RR of the vehicle rotate in the direction corresponding to the backward moving direction of the vehicle and neither the brake pedal 10 the accelerator pedal is still operated. In step S115, a pressure increase control then increases the working fluid pressure in the wheel cylinder 21 by a predetermined pressure amount ΔPI, so that a relatively small braking force is exerted on the corresponding wheel in order to reduce its speed.

Now is back on 2 Referred; the brake actuator 200 is operated to increase the pressure of the working fluid in the wheel cylinder in such a way that the cut-off valve 210 is excited, which closes the suction valve 240 is excited, which opens it, and the motor 50 is operated to the pump 51 to drive, creating working fluid under pressure to the wheel cylinder 21 is promoted. In this state, the working fluid flows through the lines 203 . 201 to the wheel cylinder 21 directed. After sufficient time has passed for the working fluid pressure to rise by the predetermined pressure amount ΔPI, the holding valve is activated 220 excited, which closes it by the ΔPI increased pressure in the wheel cylinder 21 to keep. The increase in pressure by ΔPI, a predetermined increment value, results in an increase in the braking force applied, which prevents the wheel from locking.

The control described above is carried out to the braking systems 20 of the wheels FL, FR, RL, RR to regulate. As a result, a braking force is applied to the wheels rotating in the direction in which the vehicle is moving, thereby reducing the speed of movement of the vehicle.

Next, in the steps S102 and S104 the target driving direction of the driver and the actual direction of travel of the vehicle. Since the flag F1 with the execution of the Backward slipping moderation control is set to 1, YES is obtained in the subsequent step S106, and the process goes to step S115.

The control routine of the in 4 The flowchart shown is executed on the assumption that the vehicle driver moves his foot away from the brake pedal towards the accelerator pedal. The backward movement limitation control is therefore preferably ended when the vehicle driver operates the accelerator pedal and the actual direction of travel of the vehicle changes accordingly in such a way that it is in line with the target direction of travel of the vehicle driver. In step S115, depending on the determination made in step S102 and step S104, it is determined whether the target driving direction of the vehicle driver coincides with the actual driving direction of the vehicle. If the target driving direction of the vehicle driver coincides with the actual driving direction, YES is obtained in step S115, and the process goes to step S130 and the subsequent steps. The control concept for ending the backward movement limitation control in step S130 and the subsequent steps will be explained later.

Even in the case where the vehicle is still moving, the backward movement limit control is preferably terminated when a certain wheel is due to the translation of the driving force of the internal combustion engine 1 begins to turn in the direction desired by the driver. If, despite the application of a braking force in the previous routine, the actual traveling direction is opposite to the target driving direction of the vehicle driver, NO is obtained in step S115, and the process goes to step S116. In step S116, it is determined whether the direction of rotation of the wheel to be controlled is in line with the target direction of travel of the vehicle driver. if YES is obtained in step S116, the process goes to step S130 and subsequent steps. Accordingly, the backward movement limitation control applied to the respective wheels of the vehicle is terminated in order when the wheel rotation direction coincides with the target travel direction of the driver who operates the accelerator pedal.

As long as the bike is in the Backward movement direction of the vehicle is rotating, NO is obtained in step S116, and the The process goes to step S118.

In step S118, it is determined whether the count value T of the timer started in step S112 is at or below a predetermined threshold value Ta. The threshold value Ta is set in such a way that the driver is not led to believe that the vehicle can drive backwards on the ascending road at the current backward movement speed, as well as to various valve systems, such as. B. the interruption valve 210 , which is part of the brake actuator 200 to protect against the heat resulting from the continuous excitation of these valve systems. The threshold value Ta can take into account the concept, the service life of the brake actuator 200 and the like can be determined. The threshold value Ta can be set to 3 seconds, but is not limited to this.

When the timer count T is at or is below the threshold Ta, an affirmative answer is given in step S118 YES is received, and the process goes to step S120.

If the execution of the Reverse motion limit control rotates the bike gradually reversed on the ascending road. If but the frictional force between the road surface and the wheel contact patch relative is small, for example if the vehicle is on a road with a relatively small coefficient of friction (μ), the wheel can be exercised Block the braking force determined in step S114. Therefore, in Step S120 determines whether the wheel to be controlled is not rotating, because it blocks.

If the wheel is not blocked, NO in step S120, and the process goes to step S122, in which the wheel cylinder pressure determined in the previous routine is held.

On the other hand, if the wheel locks up YES in step S120, and the process goes to step S124. In step S124, pressure reduction control is carried out to reduce the working fluid pressure in the wheel cylinder by an amount ΔP2 (ΔP1> ΔP2).

It'll open up again 2 Referred; the brake actuator is used to carry out the pressure reduction control 200 actuated in such a way that the pressure control valve 230 in response to the control signal applied, the duty cycle of which is regulated. The actuation of the pressure control valve 230 allows that between the holding valve 220 and the wheel cylinder 21 stored working fluid via the pressure control valve 230 in the expansion tank 40 flows. This actuation of the pressure control valve 230 is for a given Running time that is long enough to reduce the pressure of the working fluid in the wheel cylinder 21 around Δ P2 is guaranteed. After the specified duration, the pressure control valve 230 de-energized and closed, whereby the working fluid pressure in the wheel cylinder is reduced by ΔP2 21 is held.

If YES in step S120 what shows that the wheel to be controlled is blocking, the process goes subsequently to step S124, in which the pressure reduction control discussed above is carried out. The pressure reduction control executed in step S124 is repeated until the wheel no longer locks. The aforementioned control routine allows thus a reduction in the speed of the backward movement rotating wheel and at the same time prevents the wheel from locking.

Reference is again made to step S118; if NO is obtained in step S118, which indicates that the backward movement limitation control has already been carried out for a period longer than the threshold value Ta, the process goes to step 126 , in which it is determined whether the count value T of the timer is at or below another predetermined threshold value Tb (Ta T Tb). The threshold value Tb represents a duration over which the regulation for moderate pressure reduction in the step 128 may be run continuously. The threshold value Tb preferably represents the estimation time that the vehicle driver needs to get his foot off the brake pedal 10 or accelerator pedal away, and to make sure the working fluid pressure in the wheel cylinder 21 decreases with a small pressure decrease gradient, thereby preventing pressure decrease with a steep gradient. The threshold Tb can be set to about 8 seconds, but is not limited to this.

It is then determined in step S126 whether the count value T the timer over Ta and is at or below the threshold Tb, d. H. whether Ta <T ≤ Tb. If if YES is obtained in step S126, the process goes to step S128, in which the regulation for moderate pressure reduction accomplished is to follow the backward movement limit control and after quitting.

Generally, the brake actuator stops regulating 200 the motor 50 stopped; in addition, the valve systems, such as. B. the interruption valve 210 , the holding valve 220 , the pressure control valve 230 and the suction valve 240 , but excited. Accordingly, the cut valve 210 and the holding valve 220 open, whereas the pressure control valve 230 and the suction valve 240 getting closed. As it is in the graph of 5 is shown, the working fluid pressure in the wheel cylinder is kept at a predetermined value after the start of the backward movement limitation control at time T (= 0) until the end of the predetermined duration Ta; immediately after the predetermined time Ta, the actuation of the brake actuator 200 completed. In this case, the working fluid pressure in the wheel cylinder is therefore rapidly reduced, as is the dash-dot line "a" in 5 shows.

In step S128, however, the control for moderate pressure reduction is additionally carried out, so that the pressure decreases more gently, as shown by the solid line "b" compared to the dash-dot line "a". the brake actuator 200 is operated to carry out the regulation for moderate pressure reduction, in which the pressure control valve 230 is driven based on a control signal with a duty cycle of about 10% while the cut-off valve 210 and the holding valve 220 are excited, thereby closing them. It should be noted that the pressure control valve 230 when applying a control signal with a duty cycle of 100 is fully open.

The above-described regulation for moderate pressure reduction enables that between the holding valve 220 and the wheel cylinder 21 stored working fluid via the line 202 to the expansion tank 40 flows back, the pressure control valve 230 appropriately controls the flow rate of the working fluid. Therefore, the working fluid pressure in the wheel cylinder increases 21 little by little as it is in 5 solid line "b" shown.

During the moderate pressure reduction control, if NO is obtained in step S126, that is, if the timer count T is above the threshold Tb, the process goes to step S130 and the subsequent steps to carry out the completion process of the backward movement limitation control normally. In the termination process is the operation of the engine 50 stopped and all valve systems are de-energized. Accordingly, the cut-off valve 210 and the holding valve 220 opened while the pressure control valve 230 and the suction valve 240 getting closed. In this state, the working fluid pressure in the wheel cylinder 21 reduced with a relatively steep pressure reduction gradient. In this regard, the use of the predetermined threshold Tb allows the termination process to be initiated only when the working fluid pressure is sufficiently reduced, thereby preventing the braking force applied to the vehicle from suddenly and drastically changing.

Then, the process goes to Step S132, in which the count value reset the timer becomes. In step S134, the flag F is then set to "0" again, which leads to the next cycle the control routine is gone.

Steps S130-S134 for ending the backward movement limitation control are also carried out if the actual direction of travel of the vehicle coincides with the target direction of travel, ie YES in step S115 is held, or when the direction of rotation of the wheel is in accordance with the target direction of travel, that is, YES is obtained in step S116, during the period in which the timer count T is at or below Tb, or when NO is obtained in step S126 because the count value T of the timer is above the threshold value Tb.

Steps S130-134 are also performed to terminate the backward movement limit control when the brake pedal is operated during the execution of the backward movement limit control (flag F = 1) 10 is recorded by the driver. However, this step is in the flowchart of 4 Not shown.

Furthermore, in the driving state control system according to this embodiment of the invention, the pressure control valve 230 during the time the count value T is above the threshold value Ta and at or below Tb, ie Ta <T ≤ Tb, operated on the basis of a control signal with a duty cycle of 10%. However, the duty cycle does not have to be kept constant as long as the resulting pressure reduction gradient is smaller than the pressure reduction gradient that the in 5 dash-dot line shown "a" represents. The pulse duty factor of the control signal can be changed step by step, for example.

The actual direction of travel detected in step S104 must continue of the vehicle is not exactly as described above be determined. For example, in the case where there are three Wheels in turn in the same direction, this direction as the actual direction of travel of the vehicle can be determined. In the case of a motor vehicle with Two-wheel drive can change the direction of rotation of an idling wheel, d. H. drive-less wheel than the actual direction of travel of the vehicle be determined.

In addition, the actual direction of travel of the Vehicle directly using a ground speed sensor be recorded. The ground speed sensor installed in the vehicle generates an ultrasonic signal with a predetermined frequency in Direction to the road and back to the vehicle that reflected the Wave picks up. When the frequency of the reflected wave is higher than that of the ultrasonic signal determine that the vehicle is reversing. If the frequency of the reflected wave is smaller than that of the ultrasonic signal, let yourself determine from this that the vehicle is moving forward.

In the first embodiment, that begins in the flowchart of FIG 4 shown control routine when the ignition switch is turned on. The control routine can also be initiated, for example, if the shift lever is brought into any forward or reverse shift position and the brake pedal 10 and the accelerator pedal is not pressed.

In the first embodiment the braking force is over regulated the working fluid pressure. However, the braking force can also by pressing one regulate electronic engine brake that generates a braking force. In this case, if the count value T exceeds the threshold value Ta and is at or below the threshold Tb, d. H. Ta <T ≤ Tb, the regulation for moderate pressure reduction executed in the way that the braking force generated by the electronic braking system is light is reduced and thus has a pressure reduction gradient served, which is smaller than the gradient in a normal termination.

In the first embodiment, the brake actuator in the in 2 vacuum booster brake system shown used. However, any type of brake actuator can be used as long as the brake actuator is capable of generating braking force regardless of the driver's brake application. Therefore, a brake actuator of a hydraulic booster brake system and a motor-operated actuator can also be used to generate a braking force.

The driving state control system described above for a Vehicle contains the control unit for exerting a braking force on the Wheel that turns in the actual direction of travel of the vehicle when the Target driving direction of the driver is opposite to the actual direction of travel of the vehicle. The system also includes the termination of the control operation of the control device of the braking device after a continuous execution the regulation on a predetermined duration.

This arrangement is effective in that driver for actuation of the brake and accelerator pedal, and at the same time prevents the driver is led to believe that the backward movement speed of the Vehicle is under control. This arrangement is further effective in that continuous operation of the braking device via a long duration is avoided, thereby protecting the braking force generating device is obtained.

The driving state control system described above for a Vehicle allows the control unit to brake the device so regulates that the braking force exerted on the wheel with a gradient decreases, which is smaller than the gradient in the case where the Regulation of the braking force generating device immediately ended becomes.

This arrangement makes it possible to prevent a relatively drastic change in the backward speed of the vehicle and to notify the driver that the control for reducing the backward speed of the vehicle is ended. This arrangement also gives the vehicle operator sufficient time to depress the brake pedal or accelerator pedal to operate.

Embodiment 2

6 FIG. 14 is a flowchart illustrating a control routine according to a second preferred embodiment of the invention to be executed when the vehicle moves backward on an uphill road to limit the backward movement state of the vehicle. The controls carried out in steps S112 – S200, S120 – S124 and S120 – S200 are described in detail. A description of the same steps as in the flowchart control routine of 4 is omitted according to the first embodiment.

It is based on the flowchart of 6 Referred; In step S112, the timer is started to measure the time elapsed since the start of the backward movement limit control. The process then goes to step S200, in which for the according to the in 6 shown flowchart to be controlled wheel fluid pressure control is performed. The fluid pressure control is carried out to determine the working fluid pressure in the wheel cylinder 21 to regulate to a target pressure P, which will be explained later.

Now is back on 2 Referred; during the pressure increase control the brake actuator 200 actuated in such a way that the cut-off valve 210 is excited, which closes the suction valve 240 is excited, which opens it, and the motor 50 is operated to the pump 51 to drive and thereby the working fluid under pressure to the wheel cylinder 21 to promote. In this state, the working fluid flows through the lines 201 . 203 to the wheel cylinder 21 directed. As soon as there is enough time for the working fluid pressure in the wheel cylinder to rise 21 to the set pressure P, the holding valve 220 energized, whereby it is closed to keep the working fluid pressure in the wheel cylinder at the target pressure P. A special procedure for setting the target pressure P will be described later.

The above regulation applies to all braking systems of the wheels FL, FR, RL, RR executed, so the wheels, that turn in the direction the vehicle is moving backwards each experience a suitable braking force. As a result, the Backward movement speed of the Vehicle can be reduced.

Then in steps S102 and S104 of the flowchart of 6 determines the target driving direction of the vehicle driver and the actual driving direction of the vehicle. If the backward movement limit control has already been initiated, the flag F is set to 1. Therefore, YES is obtained in the next step S106. The process then goes to step S114.

In step S120, the control based on Step S106 determines whether the wheel to be controlled is locked. If NO is obtained in step S120, i. H. the wheel is not blocked, the process goes to step S200. In step S200, the working fluid pressure regulated to the set pressure P in the wheel cylinder.

On the other hand, if YES is obtained in step S120, d. H. the wheel locks, the process goes to step S124. In step S124, the working fluid pressure in the wheel cylinder is reduced by ΔP.

It'll open up again 2 Referred; during the pressure reduction control, the brake actuator 200 actuated in such a way that the pressure control valve 230 is driven on the basis of a control signal with a certain duty cycle. In this state, the pressure control valve enables 230 that that's between the holding valve 220 and the wheel cylinder 21 stored working fluid to the expansion tank 40 flows back. As soon as the time to decrease the pressure by ΔP has passed, the pressure control valve 230 again de-energized, closing it to maintain the state in which the working fluid pressure in the wheel cylinder is decreased by ΔP.

If the wheel to be controlled is blocked, The process thus goes to step S124 in which the pressure reduction control accomplished becomes. The pressure reduction control in step S124 becomes so long repeated until the wheel no longer locks. The aforementioned regulation allows it, the speed of the wheel that turns in the direction in which it turns the vehicle moves to decrease and at the same time blocking the To prevent wheels.

Since the control in step S126 and the subsequent steps with the corresponding control of the in 4 shown flowchart are identical, a description of these control concepts is omitted.

7 shows a control concept for the pressure control, which in the 6 step S200 shown is to be carried out. Just like the one in the flowchart of 6 The control routine shown shows the flowchart of 7 the regulation regarding one of the wheels of the vehicle.

Since the load distribution on the respective wheels FL, FR, RL, RR changes depending on the gradient of the rising road on which the vehicle is traveling, the working fluid pressure in the wheel cylinder can 21 of each wheel can be regulated depending on the gradient of the road. In step S202, the gradient θ of the ascending road is determined using a front and rear acceleration sensor, for example 160 that detect the forward and backward acceleration of the vehicle are estimated. Since the vehicle acceleration in the forward and reverse directions varies depending on the gradient of the ascending road, the gradient θ of the ascending road can be obtained directly from the output signal of the front and rear acceleration sensors 160 can be estimated. Alternatively, the gradient of the increasing Road can be estimated using an inclination angle sensor, the change state of the rotational speed of the vehicle wheel turning backwards on the ascending road, or a geometric information available through a navigation system installed in the vehicle.

In step S204, it is determined whether the estimation gradient θ determined in step S202 is greater than a predetermined one Threshold θth. If the estimation gradient θ is the same is less than or equal to the threshold θth, i.e. H. the street one has a small gradient (NO in step S204), it is assumed that the load distribution on the wheels is not significantly different. Therefore, the process goes to step S206, where the target pressure P (the desired one Pressure in the wheel cylinder) is set to a predetermined value P0. The predetermined value P0 is determined in advance with the intention of on a rising road with a gradient smaller than the threshold θ th that Apply a suitable braking force to the wheel to block it to prevent the wheel.

On the other hand, if the estimation gradient θ is larger than the threshold value θth (YES in step S204), the process goes to step S208. In step S208, the wheel cylinder pressure is regulated depending on a change in the load distribution on the wheels due to the gradient of the ascending road. First, it is determined whether that is according to the flowchart of 6 bike to be regulated is on the ascending road above or below. This is because the load that acts on the wheels that lie on the uphill road is different from the load that acts on the wheels that are on the uphill road below. For example, when the vehicle drives up a rising road, the front wheels FL, FR are on the top, while the rear wheels RL, RR are on the bottom; when the vehicle drives down the ascending road, the rear wheels RL, RR are up, while the front wheels are down.

If the wheel is on the ascending Road upstairs (YES in step S208), the process goes to step S210 in which the set pressure P is set to the predetermined value P1. If the wheel is down on the ascending road (NO in step S208), the process goes to step S212, in which the target pressure on the predetermined value P2 (P2> P1) is set.

The following is an example of a change of the concept of the target pressure distribution on the front wheels and rear wheels of a vehicle when the vehicle starts up on an uphill road. If the estimation gradient θ is the same is less than or equal to the threshold θth, i.e. H. a relatively small one Gradient before, the front wheels is a target value Pf1 and the rear wheels a target value Pr1 assigned. On the other hand, if the estimation gradient θ is larger than the threshold value θ th, the front wheels a target value Pf2 and a target value Pr2 assigned to the rear wheels. In the case where the vehicle drives up an uphill road, takes the on the rear wheels acting load with an increase in the gradient of the ascending road during the on the front wheels acting load decreases. Therefore, the target value Pr2 becomes larger than the target value Pr1 is set. The target value Pr2 can be with a Increase in the gradient of the ascending road. Besides, can the nominal value Pf2 can be set smaller than (Pf1 / Pr1) * Pr2, d. H. Pf2 <(Pf1 / Pr1) * Pr2.

In steps S210 and S212, the target pressures P1, P2 of the aforementioned relationship are specified sufficiently. Since the flowchart of 7 shows the control routine executed for a wheel, the target pressures P1, P2 are set for the front and rear wheels, respectively.

As soon as the target pressure value P is set to take account of the gradient θ of the rising road, the process goes to step S214. In step S214, the currently selected gear of the translation device 3 depending on the output signals of the gear sensor 150 read that to detect the position of a shift lever to select the gear of the translation device 3 is designed.

In the subsequent step S216, it is determined whether in the translation device 3 the fast gear is selected for a quick translation. In the case where the overdrive is selected, the vehicle is likely to move down the ascending road because the gear ratio of the overdrive is relatively small. If the overdrive is selected, YES is obtained accordingly in step S216. Then, the process goes to step S218, in which the target value P set in step S206, S210 or S212 is set by adding a predetermined compensation value P3 to the target value P. The process goes to step S220. Since the target pressure P is compensated for, ie increased by the value P3, a greater braking force is exerted on the wheel to be controlled, which prevents an increase in the speed of backward movement. If in the translation device 3 on the other hand, if the slow speed is selected for a translation into slow speed, NO is obtained in step S216. Then the process goes straight to step S220 without updating the target pressure value P. The control carried out in steps S216 and S218 makes it possible, depending on the movement state of the vehicle, which is dependent on the selected gear position of the transmission device 3 changes to apply a suitable braking force to the wheel.

In step S220, the acceleration α with which the vehicle moves backwards on the ascending road is estimated. For example, the vehicle movement speed is estimated by taking the average of the speeds of the wheels turning backwards on the rising road is determined. The acceleration α of the vehicle can then be estimated as a function of the size of the change in the speed of movement of the estimation vehicle per unit time.

In step S222, it is determined whether the estimation acceleration α is larger as a predetermined threshold αth. If the acceleration α is equal which is or less than the predetermined threshold value αth NO in step S222, and the process goes to step S226 without updating the target pressure P.

If the acceleration α against it is bigger than the predetermined threshold value αth, YES is obtained in step S222, and the process goes to step S224. In step S224, the target pressure P is updated by a compensation value P4 is added. Since the target pressure P is compensated, d. H. is increased by P4, is to be regulated Wheel a greater braking force exercised. Since the target pressure P taking into account the acceleration α of the vehicle moving speed is determined, the process carried out in steps S220 to S224 is a regulation. The braking force exerted on the wheel can be therefore determine more appropriately. It also enables in steps S220 up to S224 Process that at the beginning of the backward movement of the vehicle a relatively large one Braking force applied becomes. As a result, an increase in the speed of movement of the vehicle are effectively kept within limits.

Once the target pressure P is determined, the process goes to step S226, where the brake actuator 200 is actuated as a function of the determined target pressure P; then the regulation of the in 7 shown flowchart to the end.

In the flowchart of 7 the target pressure P is compensated in steps S222 and S224 if the acceleration α of the vehicle movement speed is greater than the threshold value αth. As an alternative to this, the compensation value P4 is set as a function of the acceleration α such that the more the acceleration α increases, the greater the compensation value P4.

Further, in the driving state control system according to this embodiment of the invention, the pressure control valve 230 depending on the control signal with a duty cycle of 10% during the time in which the count value T is above Ta and at or below Tb, ie Ta <T ≤ Tb. However, the duty cycle does not have to be kept constant, provided the resulting pressure reduction gradient is less than the pressure reduction gradient that the in 5 dash-dot line "a" shown. The duty cycle of the control signal can be changed gradually, for example.

Furthermore, the step S104 recorded actual direction of travel of the vehicle is not detected exactly in the manner discussed above become. For example, if three wheels turn in the same direction, this direction is determined as the actual direction of travel of the vehicle become. In the case of a motor vehicle with two-wheel drive, the Direction of rotation of an idling wheel, d. H. driveless wheel, be determined as the actual direction of travel of the vehicle.

In addition, the actual direction of travel of the vehicle using a ground speed sensor be recorded immediately. The ground speed sensor installed in the vehicle generates in particular an ultrasound signal with a predetermined frequency to the road and back again to the vehicle that receives the reflected wave. If the frequency of the reflected wave is larger than that of the ultrasonic signal, it can be determined that the vehicle in reverse drive located. When the frequency of the reflected wave is lower than that of the ultrasonic signal, it can be determined that the vehicle in forward drive located.

In the second embodiment, that begins in the flowchart of FIG 6 shown control routine with turning on the ignition switch. The control routine can also be initiated, for example, when the shift lever is brought into any forward or reverse shift position and the brake pedal 10 and the accelerator pedal is not operated.

In the second embodiment the braking force is over regulated the working fluid pressure. The braking force can also be applied the actuation an electronic engine brake to generate a braking force be managed. In this case, if the count T is above Ta and at or below Tb, d. H. Ta <T ≤ Tb, the regulation for moderate pressure reduction executed in the way that the braking force generated by the electronic braking system is slowly reduced and thus a braking force reduction gradient which is less than the gradient of normal termination.

Embodiment 3

A driving state control system will now be described according to one third preferred embodiment the invention.

If a vehicle was moving backward on an uphill road, the vehicle operator would depress the accelerator pedal to move the vehicle forward. If the vehicle is driving on the ascending road with a small μ, for example on an icy road, at least one wheel of the vehicle can spin. 8th FIG. 12 is a flowchart showing a control routine for limiting the backward state of the vehicle in the case where at least one wheel is spinning. Because the wheels of the vehicle are regulated individually, is the flowchart of 8th just like the one in 6 and 7 The flow diagrams shown are only shown for one wheel.

The control routine of the in 8th The flowchart shown begins when the ignition switch is turned on.

In step S302, it is determined whether that executed in step S312 Backward slipping moderation control and / or a slip limit control executed in step S314 are already in progress. If the backward movement limit control or the slip limitation control is already being carried out, the control routine is ended without performing the following steps.

If neither the backward movement limitation control executed in step S312 nor the slip limitation control executed in step S314 is in progress, NO is obtained in step S302. The process then goes to step S304, in which the output signals of the sensors 110 . 120 . 130 . 140 . 160 and the switch 150 , in the 3 shown are read.

In step S306 is dependent from the read output signals determines whether the vehicle is on a rising road moved backwards. In the aforementioned case, in which the vehicle is on a road moved backwards with a small μ and at least one wheel spins, the directions of rotation are correct FL wheels, FR, RL, RR do not match. If the direction of rotation of at least one wheel of the vehicle is not with those of the rest Wheels coincides can accordingly be determined that the vehicle is moving backward. This arrangement enables it to determine the state of motion of the vehicle earlier than via the Difference between the wheel speeds.

Alternatively, the backward movement state of the vehicle may be performed in accordance with the procedure in steps S102, S104 and S114 of FIG 6 The flowchart shown can be determined if the target driving direction of the vehicle driver does not match the actual driving direction of the vehicle. The backward movement status of the vehicle can be determined if at least one wheel of the vehicle rotates in a direction that is opposite to the desired direction of travel of the vehicle.

After the determination in step S306, whether the vehicle is moving backwards The process goes to step S308, in which it is confirmed whether the vehicle is moved backwards. If it is determined that the vehicle is not moving backward, i. H. If NO is obtained in step S308, the control routine becomes completed. If it is determined that the vehicle is moving backwards, d. H. If YES is obtained in step S308, the process goes to step S310.

In step S310, it is determined whether the wheel to be controlled by the control routine in the direction rotates in which the vehicle moves backwards. If the wheel in the direction the vehicle is moving backwards YES is obtained in step S310, and the process goes to step S312, in which the backward movement limit control is initiated. When the wheel turns in the opposite direction to the backward direction Direction turns, it can be determined that the wheel due to the small Friction coefficient on the road with the small μ goes crazy. In this case, NO is obtained in step S310, and the process goes to step S314 where slip control is initiated becomes.

As soon as a control is initiated in step S312 or in step S314, in step 302 YES is obtained, and the control routine is ended without executing the subsequent steps S304 to S314. Once the control initiated in step S312 or step S314 is finished, NO is obtained in step S302 and the process goes to step S304 and subsequent steps.

9 FIG. 14 is a flowchart illustrating the backward movement limit control routine to be executed in step S312. The control routine of the in 9 The flowchart shown is essentially the same as the control routine of FIG 6 shown flowchart. Therefore, for the same steps of the in 9 flowchart shown as in the in 6 shown flowchart also uses the same reference numerals.

In the flowchart of 9 step S108 of FIG 6 , At the beginning of the control routine of the flow chart of 9 it is determined in step S106 whether the flag F1 is set to 1 to confirm the state of the backward movement limit control. Since the flag F is set to 0 immediately after the start of this control routine, NO is obtained in step S106, and the process then goes to step S110, in which the flag F is reset to 1 to indicate that the backward movement limit control is being executed. Then in step S112, the timer is started to measure the elapsed time after the start of the backward movement limit control. The process goes to step S200, in which the fluid pressure control is carried out based on 6 has been described.

In the next cycle of the control routine, YES is obtained in step S106 because the flag F1 has been set to 1, and the process goes to step S101. Then, step S101 and the subsequent steps are carried out as shown in FIG 6 shown flowchart is shown.

As it is in the flowchart of 6 is shown, the control in steps S130 to S134 of the in 9 shown flowchart ended during repeated executions of the routine, if the actual direction of travel of the vehicle corresponds to the target direction of travel (YES in step S114), if the direction of rotation of the wheel corresponds to the target direction of travel (YES in step S116), and if the timer value T exceeds the threshold value Tb (NO in step S126 ).

The backward movement limit control is also performed through steps S130 to S134 upon detection of the operation of the brake pedal 10 completed.

10 FIG. 14 is a flowchart illustrating a control routine of the slip limit control that is executed in step S314 of FIG 8th shown flowchart is to be executed.

At the beginning of the 8th The flowchart shown is determined in step S502 whether the flag F2 is set to 1 to indicate that the slip limitation control is being executed. Since the flag F2 is set to 0 immediately after the start of the control routine, NO is obtained in step S502, and the process goes to step S504 to set the flag F2 to 1, which indicates that the slip limit control is being executed. In step S506, a predetermined pressure value P5 is set to the target pressure P (ie the target wheel cylinder pressure). The predetermined pressure value P5 is set for the purpose of limiting or preventing movement of the vehicle. In step S508, the operation of the brake actuator 200 depending on the set pressure P set in step S506.

In the next cycle of the control routine, YES is obtained in step S502 because the flag F2 has been set to 1, and the process goes to step S510 to read the output signals from the sensors 110 . 120 . 130 . 140 . 160 and the switch 150 produce.

In step S512 depending on the output signals of the sensors 110 . 120 . 130 . 140 . 160 and the switch 150 determines whether the vehicle is moving backwards on an uphill road. As in step S306 of FIG 8th The flowchart shown in step S512 of the in FIG 10 shown flowchart determines whether the directions of rotation of all wheels FL, FR, RL, RR match. If they do not match, it is determined in step S512 that the vehicle is moving backward. Alternatively, it can be determined that the vehicle is moving backward if the target direction of travel does not correspond to the actual direction of travel of the vehicle. Furthermore, it can be determined that the vehicle moves backwards if at least one wheel of the vehicle rotates in a direction opposite to the target direction of travel.

In the subsequent step S514 will be confirmed, whether the backward movement of the Vehicle was determined. If it was determined in step S512 that the vehicle is moving backwards YES is obtained in step S514. The process then goes to step S515.

In step S515, it is determined whether the wheel to be controlled is based on the control of the in 10 shown flowchart rotates in the direction that corresponds to the target direction of travel of the vehicle. The execution of step S515 is part of this slip limitation regulation in order to take into account a change in the frictional state of the road surface with which the wheel is in contact when the vehicle is moving backwards. For example, in the case where the vehicle is reversing on a partially icy lane of the ascending road, the direction of rotation of the wheel may reverse when the wheel comes from an ice-free area to an icy area of the lane. The wheel starts. thus turning in the direction in which the vehicle is moving backwards. Therefore, when the wheel starts rotating in the reverse direction, NO is obtained in step S515, and the process goes to step S526 to end the slip limiting control routine. In this case, the process goes to step S312 of the in 8th shown flowchart to initiate the backward movement limit control.

Similarly, the change in the frictional condition of the road surface may result in the wheel spinning, which turns in the direction in which the vehicle is moving backward. Under this condition, the direction of rotation of the wheel coincides with the target direction of travel. Accordingly, in step S116 of the in 8th YES shown flowchart obtained. Next, step S130 and subsequent steps are executed to end the backward movement limit control. When the backward movement limit control is finished, the process goes to step S314 of FIG 8th shown flowchart back to initiate the slip control.

It'll open up again 10 Referred; if the direction of rotation of the wheel coincides with the target direction of travel, YES is obtained in step S515. The process goes to step S516 to set a slip amount ΔV of the wheel to be controlled. An example of a common regulation for limiting wheel slip is traction control. The function of the traction control is to limit the amount of acceleration slip that can occur when the vehicle is started or accelerated. In general, the deviation between a reference speed of the wheel, which is determined as a function of a desired slip and the estimated vehicle speed, and the actual speed of the wheel is determined. The amount of the deviation between the reference speed and the estimated vehicle speed is set as the slip amount ΔV of the wheel. The control routine of the in 10 shown river slide However, it should be carried out on the condition that the vehicle moves backwards on a rising road and a wheel spins. Thus, the condition under which the control routine is to be used differs from the condition under which the traction control is carried out. Therefore, the detected wheel speed is expediently set to the slip amount ΔV of the wheel, as is the case in the control routine in the flowchart of 10 is shown. This arrangement is essentially consistent with the assumption that the estimation vehicle speed is zero.

In step S518, it is determined whether the slip amount ΔV set in step S516 is equal to or less as a threshold ΔVth is. If the slip amount ΔV is smaller than the threshold value ΔVth, for example, the wheel locks (NO in step S518), the goes Process to step S524. In step S524, that in the last cycle selected in the control routine Target pressure P as the target pressure P for the current cycle of the control routine held.

The process goes to step S508, in which the control of the operation of the brake actuator 200 depending on the set pressure P set in step S524.

When the slip amount is equal to ΔV that or greater than the threshold value ΔVth is YES in step S518, and the process then goes to Step S520.

In step S520, the change in the speed of the according to the in 10 flow chart to be controlled wheels confirmed. For this purpose, the deviation between the slip amount ΔV set in step S516 in the last cycle of the control routine and the slip amount ΔV set in step S516 in the current cycle of the control routine is determined. Then the time interval between the last step S516 and the current step S516 is also determined. The wheel acceleration is determined as a function of the determined deviation and the time interval. It is determined in which direction the determined acceleration has changed, ie "+", "-" or "0", as in 11 is shown. If the absolute value of the wheel acceleration is a predetermined small value (the change in the wheel speed is in a predetermined minute range), it is determined that neither an increase nor a decrease in the wheel acceleration is required. On the other hand, if the absolute value of the wheel acceleration increases or decreases and thus deviates from the specified range, the acceleration is determined as (+) or (-).

In step S522, the target pressure P is set as a function of the determined state (+, -, 0) of the change in the wheel acceleration in step S520, with reference to FIG 11 shown diagram is referenced. As it is from the diagram of 11 can be seen, in the event that the wheel acceleration decreases (-), the target pressure P is maintained, ie the pressure value P that was set in the last cycle of the control routine is set to the pressure value P for the current cycle of the control routine. If the wheel acceleration remains essentially constant (0), the target pressure P is increased, ie a predetermined pressure P6 (P6> 0) is added to the pressure value P set in the last cycle of the control routine, and then the pressure value obtained (P + P6 ) is set to the pressure value P for the current cycle of the control routine. if the wheel acceleration increases (+), the target pressure P is increased rapidly, ie a predetermined pressure P7 (P7> P6) is added to the pressure value P set in the last cycle of the control routine, and then the pressure value thus obtained (P + P7) set to the pressure value P for the current cycle.

After the determination of the target pressure P in step S522, the process goes to step S508 in which the operation of the brake actuator 200 depending on the set pressure P set in step S522.

If the vehicle as a result of repeated execution the aforementioned control routine stops moving backward in step S514 NO received, and the process goes to step S526. In step S526 executes a predetermined control termination, and the process goes to step S528. In step S528, the flag F2 reset from 1 to 0, which ends the slip limit control.

The slip limit control enables the braking system 20 exerts a braking force on a spinning wheel, thereby preventing wheel slip. The slip limit control therefore acts as a slip limit differential that limits wheel slip. If the vehicle does not have a slip limitation differential, the slip limitation control serves to prevent a loss of drive torque of the spinning wheel and, at the same time, a decrease in the torque to be exerted on the non-spinning wheel.

When the vehicle starts to get in from the driver desired Direction, and has a spinning wheel, the aforementioned traction control initiated the acceleration slip limit the vehicle.

In the third embodiment, the brake actuator in the in 2 vacuum booster brake system shown used. However, any type of brake actuator can be used as long as the brake actuator is capable of generating braking force regardless of the braking performed by the driver. Therefore, a brake actuator of a hydraulic booster brake system as well as an actuator can be used to generate the braking force by motor become.

The wheel speed sensor used in these embodiments 110 is able to record both the speed and the direction of rotation of the wheel. The wheel speed sensor 110 But can also be formed from a sensor for detecting only the speed of a wheel, and it can be in addition to the wheel speed sensor 110 another sensor for detecting the direction of rotation of the wheel can be provided.

Although the invention is by reference to the preferred embodiments It should be noted that the invention is not to the preferred embodiments or configurations limited is. Rather, the invention extends to various types Modifications and equivalent arrangements within the the requirements defined basic idea of the invention.

Claims (15)

Driving state control system for regulating the braking force exerted on a vehicle when the actual direction of travel of the vehicle is opposite to the target direction of travel of the vehicle in accordance with the vehicle operating state selected by the driver, comprising: a vehicle operating state detection device ( 120 ) which determines whether the vehicle operating state selected by the driver is the forward drive or the reverse drive; an actual travel direction detection device ( 110 ), which records the actual direction of travel of the vehicle; a braking device ( 200 ) that applies a braking force to a specific wheel regardless of the brake application performed by the driver; and a control unit ( 100 ) that the braking device ( 200 ) in such a way that the braking force is exerted on a wheel that rotates in a direction corresponding to the actual direction of travel of the vehicle when the operating state detection device ( 120 ) certain target direction of travel of the vehicle is opposite to the actual direction of travel of the vehicle detected by the actual direction of travel detection device, characterized in that the control device ( 100 ) after a continuous activation of the braking device for a predetermined first period of time, the activation of the braking device stops in order to stop the application of the braking force. Driving state control system according to claim 1, wherein the vehicle operating condition based on the position selected by the driver a shift lever of the vehicle is determined. Driving state control system according to claim 1 or 2, the actual direction of travel based on the direction of rotation at least one wheel of the vehicle is determined. Driving state control system according to one of claims 1 to 3, the braking force by the hydraulic pressure of a working fluid of the vehicle is regulated. Driving state control system according to one of claims 1 to 3, the braking force by an existing electronic in the vehicle Brake is regulated. Driving state control system according to one of claims 1 to 5, wherein when the wheel on which the braking force is applied blocked, the pressure applied to the wheel cylinder of the wheel by one predetermined value is reduced (S120). Driving state control system according to one of claims 1 to 6, being the one exerted on the wheel Braking force after a continuous braking force control for a period of time, the longer is shorter than one set as the first time period, second time period, and after is reduced (S126). Driving state control system according to one of claims 1 to 7, the control unit the size of the on exercised the wheel Regulates braking force, and being the size of the braking force applied based on the size of the acceleration of the vehicle is changed in the actual direction of travel. Driving state control system according to claim 8, wherein the control device ( 100 ) the braking force is distributed to the wheels above or below on a rising road so that the braking force on the wheels below increases with increasing gradient. Driving state control system according to claim 8 or 9, wherein a target pressure for wheel control based on that of driver selected Gear position of the vehicle is determined. Driving state control system according to claim 10, wherein the target pressure for wheel control based on the acceleration of the vehicle is determined. Driving state control system according to one of claims 1 to 11, further comprising a direction of rotation detection device ( 110 ), each of which detects the direction of rotation of the vehicle wheels, the control unit: regardless of a brake actuation carried out by the vehicle driver, on at least one wheel, which rotates in a direction opposite to the desired direction of travel, which is detected by the direction of rotation detection device, exerts a first braking force and on at least one wheel which rotates in a direction corresponding to the desired direction of travel, a second braking force, wherein. the first braking force on the at least one wheel, which rotates in the direction opposite to the desired direction of travel, is determined as a function of the driving state of the vehicle; and the second braking force on the at least one wheel, which rotates in the direction corresponding to the desired direction of travel, is determined as a function of the rotational state of the wheel. Method for regulating the braking force exerted on a vehicle if the actual direction of travel of the vehicle to the target direction of travel of the vehicle according to the vehicle operating state selected by the driver is opposite with: Detect whether the operating state selected by the driver the forward drive or the reverse drive is; Detecting the actual direction of travel of the vehicle; Exercise one Braking force on a particular wheel, regardless of a brake application performed by the driver; and Regulate the braking force on a wheel that is in one of the Actual direction of travel of the vehicle turns corresponding direction if the target direction of travel of the vehicle to the actual direction of travel of the Vehicle is opposite, characterized by To stop the application of braking force after a continuous application of braking force for a predetermined first time period. Method for regulating the braking force exerted on a vehicle according to claim 13, further comprising: regulating the size of the braking force exerted on the wheel, being the size of the braking force applied based on the size of the acceleration of the vehicle is changed in the actual direction of travel. Method for regulating the braking force exerted on a vehicle according to claim 13 or 14, further with: rules of distribution of Braking force on the up or down on a rising road Wheels like that that the braking force on the wheels below increases with increasing gradient gets bigger.